System of lighting and lighting unit for use therein



July 28, 1942. H. F. LORENZ 2,291,494 SYSTEM OF LIGHTING AND LIGHTING UNIT FOR USE 'THENEIN Filed Nov. 5, 1940 2 Sheets-Sheet 1 T fi- 20 Z20 w K \F\ \zz 2 I F2 20a INVENTOR Z3 fl/mowf Loki/v2 ATTORNEY July 28, 1942. H. F. LORENZ 2,291,494

I SYSTEM OF LIGHTING AND LIGHTING UNIT FOR USE THEREIN Filed Nov. 5, 1940 v 2 Sheets-Sheet 2 W W W W I l J I 1 :I

I. I 4/15 I L l l I I I l I I E I g I I .4 /7 /7 INVENTOR fi/mom La/mvz BY ATTORN EY Patented July 28, 1942 SYSTEM OF LIGHTING AND LIGHTING UNIT FOR USE THEREIN Harold F. Lorenz, Meriden, Conn., assignor to The Miller Company, Meriden, Conn., a corporation of Connecticut Application November 5, 1940, Serial No. 364,339

Claims.

The present invention relates to a system of lighting and lighting units for use therein, and is more particularly directed toward a lighting system suitable for illuminating the working areas on the opposite sides of parallel aisles.

In textile mills and factories employing batteries of machines on opposite sides of parallel aisles it is important to place a high intensity of illumination on the machines and to satisfactorily illuminate the aisle between the machines. This is usually done by some form of asymmetric equipment placed over the center of the aisle. The present invention contemplates lighting equipment for this purpose wherein each unit over the center of the aisle employs two fluorescent light sources each associated with a parabolic reflector whose axis is tilted at the proper angle to produce a sloping beam ior illuminating the machine on the side of the aisle opposite the reflector.

Asymmetric lighting equipment which would provide satisfactory lighting for the machines on opposite sides of a single aisle may havea substantial amount of light spilled at higher angles than necessary for illuminating the working areas, and this high angle spilled light falls on the machinery of adjacent aisles. This spilled light is useful for illuminating purposes, and the present invention contemplates designing the lighting systems so that this spilled light does not escape at sufliciently high angles to reach the normal eye level of the operator in the adjacent, aisle. By providing suitable cut of! angles in the reflectors employed it is possible for the operator to have the eye completely shielded so as to receive no annoying glare from the flxtures over adjacent aisles.

Other and further objects of the invention will appear as the description proceeds.

The accompanying drawings show, for purposes of illustrating the present invention, an embodiment in which the invention may take form, it being understood that the drawings are illustrative of the invention rather than limiting the same.

In these drawings:

Figure 1 is a perspective view of a lighting unit;

Figure 2 is a transverse sectional view of the same with parts in elevation;

Figure 3 is a longitudinal sectional view of the lighting unit with parts in section; and

Figure 4 is a diagrammatic view illustrating tem for illuminating working areas on opposite sides of-parallel aisles.

Thelighting unit shown has a suspension Ill by which it may be supported from above.

Two fluorescent lamps II and I2 are supported in conventional fluorescent lamp holders l3 and I4 carried on end plates IS. The lamps H and I! are received in parabolic reflectors l6 and H. these being secured to theeiid plates and to one another as indicated in the drawings. These reflectors have axial planes indicated at 20, 20

which 'slope at substantially 30 to the vertical and the parallel light rays 20a, 26b are directed downwardly, as indicated in the drawings, at substantially 30 to the vertical. The axial plane or center line of the concentration 20 is indicated in Figure 4. By mounting the fixtures at the proper height above working areas, illustrated at W in Figure 4, it will be apparent that the beams from the parabolic reflectors may be directed toward the working areas.

The lower edges 2| of the reflectors l6 and I! are substantially below the centers of the light sources I and I2 and are spaced slightly farther apart than the light sources. The highest angle direct light which can escape from the bottom or the light sources is in each instance indicated by the ray 22. When this ray is drawn in on Figure 4, it will be seen that the lighting unit in the left aisle produces direct light which spreads over the machines in the right aisle. The normal eye level of the operator is indicated by the eye E in Figure 4, and this in each instance is above the ray 2!, Hence the operator does not see the bright sources of the lighting unit in the adjacent aisle. As the lower edges 2| are more widely spaced than the light sources, it is also obvious that the limiting direct my from the light source adjacent the edge or the reflector is 40 rather steep, as indicated at 23. The dominant rays from the sources escaping past the lower edges of the reflector are indicated by the lines 24, 24a, and these lines are at substantially 90 to one another.

With the arrangement shown not only is the dominant output of the unit placed on the working areas, but a substantial amount of direct light from each source falls in the aisle under the unit and a lesser amount falls on the machines in adjacent aisles. This, produces a, well the employment of the lighting units in a sysdiffused illumination on the various surfaces of" the machine and on operations carried on in the machines, so that all parts and operations may be well lighted.

It is apparent that, within the scope or the in ing two parallel light sources at the same elevation, each source beingdisposed along the focal line of a rectilinear reflector of substantially parabolic cross section with its axial plane tilted to direct the reflected rays across the vertical plane through the center of the corresponding aisle and toward the working area on the opposite side of said aisle, the lower portions of each of said reflectors acting as light shields to limit the maximum angle above the nadir through which direct light may be emitted so as to be below normal eye level in the adjacent aisle.

2. A system of lighting such as claimed in claim 1, wherein the lower edges of the reflectors are spaced slightly wider than the light sources so that direct light from each source may be emitted at a predetermined small angle from the other side of the nadir for aisle illumination.

3. A system of lighting for illuminating working areas on the two opposite sides of parallel aisles, comprising parallel light units placed at the same height above the working areas over the centers of the aisles, each lighting unit having two parallel light sources at the same elevation, each source being disposed along the focal line of a rectilinear reflector of substantially parabolic cross section with its axial plane tilted at an angle of approximately 30 to the vertical to direct the reflected rays across the verticalplane through the center of the corresponding aisle and toward the working area on the opposite side of said aisle, the lower portions of each of said reflectors acting to limit the spread of direct light to substantially and acting as light shields to limit the maximum angle above the nadir through which direct lightmay be emitted so as to be below normal eye level in the adjacent aisle.

4. A direct lighting unit adapted for mounting over the center of an -aisle for similarly illuminating working areas on the opposite sides of the aisle, comprising two parallel horizontal long light sources, spaced a substantial distance apart and at the same level, an inwardly facing, open mouthed, parabolic,-rectilinear reflecting trough about each source, each trough being symmetrical about a downwardly sloping axial plane directed toward the working area on the opposite side of said aisle and producing a downwardly sloping beam of reflected light, the beams crossing midway between the sources so that an aisle area below the unit receives direct light mixed with diffusely reflected light, .the lower edges of the reflecting troughs being spaced substantially below their upper edges and below the sources and forming light shields each of which screens the opposite source to a predetermined angle below the horizontal and limits the direct light from r the corresponding source to predetermined angles from the nadir, whereby the area to one side of the aisle receives reflected light and direct light" from the opposite source and the immediate, but more remote area, receives direct light onlyfrom said opposite source.

5. A unit such as claimed in claim 4, wherein the slope of the axial planes ofthe reflecting troughs is substantially 30 from the vertical and the angle through which direct light escapes from each source is substantially 90.

HAROLD F. LORENZ. 

